Pituitary hormones are produced in large, uniform lots, carefully standardized, and are given free upon reasonable request by responsible investigators anywhere in the world. Available preparations are: Growth hormone, sheep and beef; Prolactin, sheep and beef; FSH, sheep, beef and pig; LH, sheep and beef; TSH, sheep and beef. Human pituitaries are also processed in behalf of the National Pituitary Agency, and human growth hormones and gonadotrophins are returned to that Agency for distribution to clinical investigators. Limited amounts of highly purified preparations are available for use in radioimmunoassay. These are: growth hormone, human, pig, dog, sheep, beef, monkey; prolactin, human, pig; FSH, human, sheep; LH, human, sheep; TSH, human; placental lactogen, human; hCG, hCG Beta- subunit. The laboratory acts as a depot for the distribution of the following antisera for use in radioimmunoassay: anti-human growth hormone, anti-human FSH; anti-human LH; anti-human TSH; anti-human prolactin; anti-hCG Beta-subunit; anti-aldosterone; anti-human placental lactogen. Other preparations available on request: relaxin; LH/FSH-releasing hormone. A continuing program of research in methods and in the chemistry of the pituitary hormones is carried out.